Nikala Smith came on at goal attack in place of Cox and the Fever lifted to another level as they slowly managed to erode the small lead the Pulse had held throughout the game.
The Pulse did their best to keep the Fever at arm's length but in the final few minutes the home side hit the front and they didn't give up their advantage.
Earlier, in Adelaide, the Canterbury Tactix were hammered 65-44 by the Thunderbirds, which confirmed they would pick up the wooden spoon for this season.
Collecting kitchen utensils in a sporting sense is an unwanted position to be in, but the Tactix have been poor all season and they slumped to their 11th defeat from 13 games.
The Southern Steel also tasted defeat 11 times this year, but the heavy nature of the Tactix' losses took its toll and they had a far worse points differential.
It was an unfair way for 32-year-old Maree Bowden to end her career at the top level after she confirmed she would retire at the end of this season.
Bowden has captained the Tactix since 2010, while veteran defender Anna Galvan has also called time on her career after playing for the franchise during the past three campaigns.
Both players previously represented the Silver Ferns and played for the Canterbury Flames in the old national league.
The Thunderbirds simply had too much class through court and put up 20 more attempts on goal than the visitors and shot with a better accuracy.
The victory booked Adelaide's spot in the post-season but who they will play in the first week of the playoffs won't be decided until the Waikato/Bay of Plenty Magic have played the Queensland Firebirds in Hamilton tomorrow night. (monday)
Results: Adelaide Thunderbirds 65 (Carla Borrego 34/37, Erin Bell 23/28, Cody Lange 5/6, Melissa Rowland 3/5) Canterbury Tactix 44 (Joanne Harten 33/41, Anna Thompson 8/11, Ellen Halpenny 3/4) 1Q: 16-6, HT: 35-17, 3Q: 47-28
West Coast Fever 40 (Catherine Cox 21/23, Caitlin Bassett 15/23, Nikala Smith 4/6) Central Pulse (Caitlin Thwaites 27/31, Paula Griffin 11/16) 1Q: 7-11, HT: 17-20, 3Q: 28-30